CH23
LG DC Link Undervoltage Error

System shows CH23 and does not operate or shuts down.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Low supply voltage, Loose line connections at outdoor unit, Faulty rectifier or DC bus capacitors on outdoor PCB

How to Fix / Troubleshooting

Safety: Disconnect power before opening the outdoor unit. High voltage components can retain charge.

Steps:

  • Verify supply voltage: Have a qualified person check that the line voltage at the outdoor unit is within LG's specified range.
  • Inspect terminals: Tighten all line and neutral connections at the outdoor terminal block. Look for discoloration or melted insulation.
  • Check for shared circuits: Avoid running the air conditioner on an overloaded circuit that may cause voltage drop.
  • Power reset: After corrections, power the system back on and test.

Technician needed: If CH23 remains with proper voltage and tight connections, the outdoor PCB DC bus circuit is likely faulty and should be replaced by a professional.

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Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Inverter PCB
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